1. Field of the Invention
The present invention generally relates to a backlight module and thermal design thereof.
2. Description of the Prior Art
Backlight module is extensively used in a variety of electronic devices such as displaying devices including laptops, tablets, televisions, or mobile phones. The laptops and the tablets are both portable computers; however, compared to the laptops, there is a greater requirement for mobility and convenience with regard to the tablets. In addition, the tablets are usually equipped with touch interfaces so that they have concise appearance. The concise appearance and the flexibility in manipulation let the users be able to use tablets or other related products at any time and any place. In other words, the tablets and other related products are not limited to be used indoors or in a specific location but can be used outdoors or versatile environment.
As FIG. 1A shows, luminance provided by the conventional backlight module such as those used in the laptops is enough for the users working indoors, but environment light may cause insufficient luminance of the displaying devices in outdoor environment. In order to enhance luminance for the displaying devices being suitable to work outdoors, the light source density may be increased. However, the way of increasing light source density may result in temperature rising of the light source module, deformation of the optical sheets, influence on rotation of the liquid crystal molecules.
As a result, it is a conventional way to use a supporting frame having greater heat conduction efficiency for backlight module, wherein the area of the supporting frame is further increased to facilitate heat dissipating. However, increasing the area of supporting frame will increase the production cost as well as the weight of supporting frame, impairing the portability and flexibility of portable computers. On the other hand, in the conventional backlight module shown in FIG. 1B, a light source module 3 is usually fastened to a supporting frame 4 by means of a single-sided adhesive tape 5; however, the light source module 3 and the supporting frame 4 are not tightly connected, resulting in an air layer A between the light source module 3 and the supporting frame 4. Since the air has a relatively small heat-conduction coefficient, the conventional backlight module 9 is not sufficient for heat conduction and heat dissipation of the backlight module 9.